The present invention relates to an apparatus for preventing exterior water conduits from freezing-up during cold weather and, in particular, to an apparatus which allows water to trickle from the conduit in response to a cold temperature being sensed.
Most dwellings are equipped with an external water conduit having a valved spigot to enable water to be accessible for watering vegetation, washing cars, etc. In the event that the ambient temperature descends to such a level that water within the conduit freezes, there exists the danger that the conduit could burst. In many dwellings, especially those without basements, there is no interior shut-off valve within the dwelling to prevent such bursting. One way of preventing the water from freezing in such dwellings involves opening the spigot very slightly to enable the water to continuously trickle from the conduit. Since running water cannot freeze, the danger of conduit bursting is avoided. However, this solution is of little use if the occupant has insufficient warning that the temperature will drop, e.g., an unexpected temperature drop during the night, or if the occupant is absent when the temperature drop occurs. Also, even if the spigot is opened to allow the water to trickle, there will occur a considerable loss of water since the water will be trickling continuously for many hours. This loss will continue even after the ambient temperature rises above the freezing level until the occupant has an opportunity to turn off the spigot (assuming that the occupant remembers to perform this task).
In order to deal with this problem, it has previously been proposed to provide water conduits with a temperature-sensitive valving which automatically opens the conduit when low temperature conditions exist, as exemplified in Jay U.S. Pat. No. 299,392 and Walters U.S. Pat. No. 4,469,118. Those devices, while in place, do not readily permit the spigot to be opened to achieve a normal water flow. Furthermore, each of those devices are actuated in response to ambient air temperature and thus will serve to trickle water when the air temperature is near the freezing temperature of water, even though the temperature of the water in the conduit may be at a higher temperature. Moreover, the device disclosed by Jay includes parts which must be attached to a dwelling wall and thus is relatively difficult to install.
It has been proposed in Van Keuren U.S. Pat. No. 1,786,878 and Stewart U.S. Pat. No. 1,161,013 to provide a mechanism for completely draining a tank of liquid when the liquid temperature reaches a predetermined low level. The temperature sensor is submerged within the liquid itself. Such a mechanism is rather complex and requires the need of a skilled laborer to install. Furthermore, if such a practice were adapted to a water conduit, the presence of a temperature sensor within the conduit would restrict the water flow during normal use of the conduit.
U.S. Pat. Nos. 1,226,696; 3,648,715; and 4,216,554 disclose other forms of temperature-sensitive valving which has been proposed.
It is an object of the present invention to provide a temperature-sensitive valving apparatus which minimizes or obviates problems of the types discussed above.
A further object is to provide such an apparatus which can be easily installed by a person unskilled and unknowledgeable with regard to plumbing.
Another object is to provide such an apparatus which is of simplified construction and enables a full water flow to be selected without removal of the apparatus.
An additional object is to minimize the waste of water by preventing water flow unless warranted by the water temperature itself.